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Calculating Nonlinear Response Functions from Gaussian-Markovian Quantum Fokker-Planck Approach Yoshitaka Tanimura Department of Chemistry Kyoto University.

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Presentation on theme: "Calculating Nonlinear Response Functions from Gaussian-Markovian Quantum Fokker-Planck Approach Yoshitaka Tanimura Department of Chemistry Kyoto University."— Presentation transcript:

1 Calculating Nonlinear Response Functions from Gaussian-Markovian Quantum Fokker-Planck Approach Yoshitaka Tanimura Department of Chemistry Kyoto University

2 In an environment ・ Fluctuation ・ Dissipation Chemical processes in condensed phase matched equilibrium Heat bath model

3 3 Model Hamiltonian (vibrational modes) T 1 + T 2 relaxationT 2 * relaxation

4 In the path integral representation (for a harmonic bath) where is the Feynman-Vernon influence functional. dissipation fluctuation

5 QFP equation for Gaussian-Markovian noise bath If we assume we have (colored noise) Markovian like noise For Hamiltonian If temp. is high

6 Density matrix elements where Time derivative of each parts are

7 we have where Then

8 We may evaluate by repeating the differentiation, then where is the density matrix for the element

9 in the Wigner representation; For nth member (similar to Kubo‘s stochstic Liouv. Eq.) Quantum Liouvillian is (YT & Kubo, JPSJ 1989)

10 G-M quantum Fokker-Planck eq (LL+SL) Quantum Liouvillian YT & Wolynes JCP 1993 YT (review), JPSJ 2006 ↑ temperature term qx (LL) + q 2 x (SL)

11 Physica meaning of Hierachy elements Dashed line represents the system-bath interactions (0 th order is exact) Major roles to calc. correlation func. (correlated effects)

12 12 Two-time correlation function (Raman spectroscopy) This can be rewritten in the Wigner representation as where A and X stand for the operators and

13 13 2D Raman (YT & Mukamel, JCP 1993) two-time variables t 1, t 2 three-body correlation function: is similarly expressed as

14 14 Example : anharmonicity 1) Harmonic 2) Morse Quantum Fokker-Planck (white noise at high temperature)

15 15 1D Raman 2body correlation func.

16 16 2DRaman Three body corre.

17 Kaufman, Heo & Fleming, PRL88, 207402(2002). 2D Raman (CS 2 ) Saito and Ohmine, PRL 88, 207401 (2002). Okumura & Tanimura, JCP 107, 2267 (1997) ExperimentMD simulationAnalytical result Anharmonisity + Nonlinear Polarizability

18 18 Noise correlation and SL interactions T 1 + T 2 relaxationT 2 * relaxation Hamiltonian

19 potential system vs. Energy-level system LL + SL interactions T 1 +T 2 T 2 * different!

20 Third-order 2D IR t 2 =0 photon echo signals?

21 Linear-Linear and Linear-Square (JPSJ review) Fast modulationSlow modulation only q x j (q+q 2 ) x j only q 2 x j

22 2D IR signal of HF liquid (from MD) Hasegawa and Tanimura, submitted to JCP Similar to slow modulation case of LL+SL model

23 Low temp. corrections of GM QFP eq. Dissipation Similar to GM caseMatsubara freq. correct. terms High (Matsubara) frequencies terms are approximated by this Fluctuation (former case was )

24 Ishizaki and Tanimura, J. Phys. Soc. Jpn. 74, 3134 (2005). GM master eq. with low temp. correction terms

25 25 Application to two-mode system Acetylacetonato Rhodiumdicarbonyl(I) (RDC) in chloroform solution Tokmakoff Group@MIT,

26 26 “ + ”corr “ - ” corr non corr Anharmonic oscillators coupled with one- or two-bath a single bath two baths

27 27 Effects of noise correlation “ + ”corr “ - ” corr non corr Ishizaki and Tanimura, J. Phys. Chem. A (2007)

28 Conclusions Quantum Fokker-Planck Eq. for GM noise colored noise, strong system-bath coupling, low temp. (w. low temp. correction terms) Variety of applications (multi-level system, etc) Multi-dimensional spectroscopy critical check for theory Review : Y. Tanimura, J. Phys. Soc. Jpn, 75, 082001 (2006).


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